Interstellar Travel: Approaching Light Speed
Interstellar Travel: Approaching Light Speed

Is interstellar travel doomed to remain in the realm of science fiction with faster than light travel and infinite improbability drives? Never mind warp speed, is light speed even possible? Technically no Light is massless and travels a little over 1 billion km/h Since spacecraft are not massless you need energy to accelerate as you keep gaining speed, you’ll need increasingly larger amounts of fuel Eventually, even tiny gains in acceleration require huge amounts of energy Getting to exactly one hundred percent light speed would require an infinite amount of energy which is why it’s an impossible goal Before we look at how close we can get to the speed of light et’s consider what we’ve accomplished so far When it comes to space travel, everything starts with a rocket still the best way we know of to literally get our feet off the ground ockets give spacecraft that initial massive boost to escape Earth’s gravity t’s the first step in getting people to the moon sending probes to the planets our sun and even the edge of our solar system pollo 10, the dress rehearsal for Apollo 11 never landed on the moon, but at reentry it did set the world record for the fastest manned spacecraft at just under 40,000 km/h in order to get all the way to the moon, it needed the help of Saturn V still the most powerful rocket ever launched The New Horizons probe, hitching a ride on the Atlas V holds the record for fastest launch velocity at over 58,536 km/h t was also the first spacecraft to reach Pluto in 2015 sending back the first detailed images ever taken of Pluto Launched in 1977, Voyager 1’s mission was the exploration of Jupiter and Saturn and once complete to leave the solar system entirely It couldn’t do it with rocket power alone so it used gravity assists at Jupiter to slingshot to Saturn and again at Saturn to fling itself out to the edge of the solar system Voyager 1 reached a top speed of 62,000 km/h but it still took over 30 years to reach interstellar space in 2012 In 1976, the Helios-2 probe set off to study the sun and the interplanetary medium To do so they were put in highly elliptical orbits with the Sun at one end and all the way out to the Earth’s orbit at the other Each time it approached the Sun the massive gravitational force sped it up to a record setting speed of 253,000 km/h the fastest any spacecraft has ever travelled Solar Probe Plus will study the corona and outer atmosphere of the sun ith an expected launch in 2018 Over the course of seven years multiple gravity assists will be used at Venus to bring it into an orbit around 7 times closer to the sun than Helios With that close of an orbit it will crush the Helios record with a top speed of just under 725,000 km/h Even still, that’s just a meager .07% the speed of light and would take over 6,000 years to travel 4 and a quarter light years to get to Proxima Centauri the closest star to our own In 2016 a planet, Proxima b, was discovered around the star It’s probably rocky like the Earth and in the right orbit to be potentially warm enough for liquid water on the surface if it has any This makes it an excellent target for the first interstellar spacecraft Staying in the realm of current or near future technology only can we improve on that speed? Ion propulsion is currently employed in some satellites but most notably, the Dawn spacecraft which studied the asteroid Vesta and the dwarf planet Ceres Inside the thruster, electrons bombard neutrally charged atoms ausing them to lose electrons and become positively charged ions Thrust is produced as they are shot out in an ion beam The resulting thrust is miniscule but since it’s fuel supply can last for years, unlike a rocket that tiny amount of thrust keeps compounding on itself and in time, it can potentially reach speeds of up to 324,000 km/h, although no spacecraft currently has While not the fastest it’s a practical method to study multiple celestial bodies in one mission an exciting potential for solar system exploration In the 1970s, the British Interplanetary Society conducted a study Project Daedalus for an unmanned fusion propelled interstellar spacecraft With help from the Tau Zero foundation in 2009 hey initiated Project Icarus to update the concept with the Ghost team’s design winning the internal competition in 2013 For propulsion, Ghost uses Inertial Confinement Fusion Small fuel pellets are shot into a fusion chamber Lasers bombard each pellet from all sides, compressing it then one final laser pulse shoots into the core, igniting the fusion process The resulting plasma is expelled from the ship, producing thrust The older Daedalus design would have reached a remarkable 12% light speed Ghost can only get to 2.33% light speed reaching Proxima Centauri in around 186 years While much slower, Ghost allows for deceleration at the star for scientific study using it’s own fusion engine and a magnetic sail 400 km in diameter Ghost also uses a more practically sourced fuel Deuterium and Tritium while Daedalus used the more efficient combination of Deuterium and Helium-3 Unfortunately, Helium-3 is too rare and inaccessible on Earth You would have to mine a gas giant like Jupiter or possibly the moon to get enough fuel Though it’s the fusion process itself that may be the biggest challenge We have yet to achieve a sustained fusion reaction in the lab Until we figure that out, these ships won’t leave the ground Weighing in at 1.4 million tonnes and over a kilometer long Ghost couldn’t launch from Earth it would have to be assembled in parts This is no small task as The International Space Station, the largest spacecraft ever built is 450 tonnes and 109 meters long, peanuts compared to Ghost Since almost all of the mass of a fusion spacecraft is fuel imagine not having to carry any with you Enter the solar sail IKAROS is a small solar sail spacecraft built by the Japanese space program JAXA Launched in 2010, it was the first successful demonstration of solar sail propulsion Similar to ion propulsion sunlight results in only a small amount of thrust but it keeps compounding on itself and only stops when the spacecraft is too far from the sun The total thrust is determined by the surface area of the sail versus the mass of the spacecraft With a big sail you can catch more light With less mass, the light can push you faster There’s also more solar energy imparted on the spacecraft the closer you can get to the sun As long as you don’t burn up in the process Unfortunately this may not be good enough to get to another star within a lifetime It would take a 1 kg spacecraft with a 1km x 1km sail travelling extremely close to the sun about 100 years to reach Proxima Centauri But we may be able to improve on this Breakthrough Starshot is another proof-of concept project to design an unmanned laser propelled spacecraft. A mothership containing thousands of nanocrafts will be launched into orbit This allows for redundancy in case of failure and a variety of payload options These tiny, gram-scale nanocraft have a sail only 4 meters to a side and just a few hundred atoms thick The Light Beamer is a ground based array of lasers that combine together in a single beam to propel each nanocraft to 20% light speed within minutes At that speed, they could reach Proxima Centauri in as little as 20 years While just a flyby mission they could get close enough to Proxima b to take pictures with enough detail to see continents and oceans if it has any While the team doesn’t see any deal breakers that could stop the project that’s not to say there won’t be any challenges especially building the light beamer At 100 gigawatts, the array would be 100 times more powerful than a nuclear power plant It will also need to contend with the scattering effects of the atmosphere as an orbital laser of this scale is too expensive Speaking of which, the projected cost is nearly 10 billion dollars about half of NASA’s 2016 budget But it does start to look like a bargain compared to the $100 billion dollar cost of the International Space Station Breakthrough Starshot may represent not only the most practical interstellar spacecraft but at 20% light speed it would be the fastest

71 thoughts on “Interstellar Travel: Approaching Light Speed”

  1. Jimiticus says:

    As a follow up, you can watch my latest video on how the Sun can be used as a gravitational lens to get a high resolution image of an exoplanet for the first time. This would be even better resolution than breakthrough star shot is capable of.

  2. WALLY SPACED says:


  3. Aalabhya Malik Anand says:

    Light is not massless, it consists of photons that have negligible mass but they are not massless.

  4. Lighthouse coffee co says:

    Ummm how the f are u getting thru the new suns Solar wind…..our heliosphere is weaker as we go out till we hit i terstellar space and its push back…but then new suns heliosphere as we go in would it not destroy our probes….and what about rogue planets and the magnetic field of them.. Shoving probes off course?

  5. Steve C says:

    Anything is possible, we just haven’t discovered how to travel at the speed of light yet, and if we work out how to manipulate space and time…we may not need to travel at SOL.

  6. Ali Talha Değirmenci says:

    so no travel if not for wormholes? well that sucks but at least we can try to save the world until then.

  7. Larry Fisher says:

    Dr. Philip Lubin, Physics Professor at the University of California, Santa Barbara, may have come up with something: photonic propulsion, which he thinks could reduce the travel time from Earth to Mars to just 3 days. The system is called DEEP IN, or Directed Propulsion for Interstellar Exploration. Even if it takes a week that's still very good.

  8. Mulga Bill says:

    In your face Archer, Kirk, Picard and Janeway!!

  9. Dr Foo says:

    According to NASA no one can get past the Van Allen belts at 385,000 feet NASA said it don't blame me

  10. gary1961 says:

    It's not light speed we need, it is 'mind speed,' the speed of the mind, which takes me billions of light years across the universe … just by thinking about it.

  11. Bassmanwcm says:

    8:11 Doc Brown…

  12. Spoon Monkey says:

    In the grim darkness of the far future, their is only war.

  13. ekrem oral says:

    No Saturn 5 is no so strong

  14. Viking says:

    Amazing…I guess we will never learn anything more about the physics of the infinite…we'll just have to keep crawling. Sorry, this is just plain (plane) obsolete understanding.

  15. Great Briton says:

    Your opening statement about the rocket needing more fuel to accelerate further and therefore more fuel to push that fuel, etc., isn't quite right. Even if you could use interstellar light to accelerate, so you don't have to carry any fuel at all, you will still struggle to approach the speed of light. This is because of relativistic effects. The amount of acceleration you get from some energy depends on how fast you are going already.

  16. Robert Gregg says:

    Unless you can create an anti gravity bubble around the craft, making the craft weightless. Don't believe everything that lightspeed deniers say. It is possible!
    We are out there right now traveling the stars. Ask anyone who works for the military industrial complex.
    All the spacecrafts people are seeing nowadays arent all aliens.

  17. Radionut ASMR says:

    they need to use deuterium / fluorine which would have a larger energy yield

  18. Bodragon says:

    (8:15) – "…nucular" ?
    Oh my daze…

  19. Tri C. Do says:

    If you sound American English then use Mile Per Hour.

  20. David s says:

    should have mentioned time dilation. How much of an effect would it have at 20% light speed?

  21. Olaf Kliemt says:

    try tesla scalar waves

  22. Greg G says:

    Your space ship looks like a meth pipe.

  23. PsiCommando says:

    I like it how for Europeans Saturn-5 is 110m tall, and for Americans it's 2and1/2 Statues of Liberty

  24. Brooke B says:

    The faster you go the longer it takes to slow down. Itll be 1000+ year journey with any near future technologies.

  25. Jon Bain says:

    rather search for the 'Astrosling'

  26. CHaiNz bUiLdz says:

    In space u need less power to travel not more

  27. foxy45 gauss says:

    the weapon I got from war robots is the 2:37

  28. Leonard Pearlman says:

    So… even IF (a big "if") you finally achieve the legendary speed o' light, is it not something like twenty thousand years to the Galactic Rim? Or Galactic Core? Maybe that's where all the cool people are! But does anyone think that's a long trip? Sort of exceeds our planning horizon I think, plus what if it takes a long time to accelerate and decelerate? I mean, your subjective trip time might approach zero, but I still think there might be serious disadvantages in such long trip times!

  29. Andy Z says:

    Even if one day we do achieve 20% speed of light what guarantee is there for debri-less interstellar space travel?

  30. Alex Povolotski says:

    You’re thinking three-dimensionally. You’re choosing the slowest possible travel methods when you can be at any point in space at any point of time, if you consider time is a thing at all.

  31. Stuart Tyler says:

    Technically there is no force acting against a spacecraft in space. No drag or anything. So it should not take more and more acceleration to go faster. Any acceleration greater than nothing will gain you speed. Bc if you let off the accelerator you would still be going the same speed forever.

  32. Sweet&SourPork says:

    Speed isn't as much a problem as shielding from said speed

  33. Barry White says:


  34. Zeke Smith says:

    He says light is mass-less. But gravity has been shown to bend light. That is a mystery science is still exploring.

  35. shawn stipe says:

    so to travel at the speed of light we must find a way to turn ourselves into light like transporter technology on star trek.?

  36. Aurel F says:

    That is nice ,but did you wonder ,the humans can resist this kind of speeds ?Our body is very fragile .The only way to travel is to build a emotional chip ,store your (self) in it ,and pass to mechanical body /imagine ,time is something biological ,if you are a machine ,you can stop your existence ,when you travel ,like a timer ,let s say 2 million years ,then wake up,for you ,the time never passed away ,because you didn t record the Time ,is like passing a second for you /here are variables like objects in the way ,the resistance of the
    metal(corosion),technological failures ,but in my opinnion ,this is more close to the truth .In fact the technology is closer day by to to build a AI -see the 7 nano chips today maded .Imagine in 200 years ?

  37. Sauga Verse says:

    Two things to keep in mind with interstellar space travel.
    First, no matter how fast you go, you also have to slow down once you arrive at your destination.
    Second, at very high speeds you run the risk of even small particles of dust destroying your spacecraft. So some sorta magnetic shield would have to be developed to deflect anything solid in the path of your spaceship.

  38. nucflashevent says:

    One of the more practical shortcuts *IF* a way can be found to achieve it would be FTL Communication. Now not to get anyone's hopes up, at the moment the Laws of Physics tell us that's just as impossible as FTL Travel. However, considering that there's a decent chance FTL Communication would be less labor intensive than FTL Travel, it could be used to remotely operate super-deep space probes. Where we send a probe to Alpha Centauri at whatever speed but if we can communicate with it instantaneously whatever its distance, then we can have humans on Earth virtually operating humanoid drones one the spacecraft…making repairs, reading instruments…both on the trip and after arrival in the Centauri system.

  39. Jay Jay says:

    So we can build a solar array that can produce 100 times the power of a nuclear power plant.. but we still have issues providing power to the planet in a sustainable and non polluting way

  40. Blitherer Masterman says:

    If reaching light speed makes your relative length infinite, maybe using negative index of refraction metamaterials to prevent the leakage of any photons will allow you to exceed it?

  41. Daniel Gadd says:

    It's not an impossible goal, or at the very least we do not know. The future can bring new technologies and understanding you fool

  42. Dee Dee says:

    Miles plz 🙄🙄🙄🙄

  43. Anastacio Castro says:

    best option is to make a moon base and start low gravity manufacturing to build large ships that are nuclear powered like u.s fleet carriers and made to colonize other planets and have resource extraction Technics

  44. Noora نورة says:

    is there a new updated video?

  45. Noora نورة says:

    I wonder why they should pay for space exploration? It should be free

  46. P Ciprian says:

    that planet is barren. No point going there as is. If we can build something to terraform Mars then we can talk about going further.

  47. NephilimFree says:

    Relativistic mass refers to mass of a body which change with the speed of the body as this speeds approaches close to speed of light, it increases with velocity and tends to infinity when the velocity approaches the speed of light.

    Relativistic mass = rest mass / squared root [one minus (velocity / speed of light) squared]

    The equation is:
    mr = m0 / sqrt (1 – v2 / c2 )

    mr: relativistic mass
    m0: rest mass (invariant mass)
    v: velocity
    c: speed of light

    The relativistic mass m becomes infinite as the velocity of the body approaches the speed of light, so, even if large momentum and energy are arbitrarily supplied to a body, its velocity always remains less than c.

  48. Mjstic Art says:

    interstellar travel with an ice pipe

  49. Bernard Alexander McNealy says:

    Hey Commander Data! Explain what a kilometer is — and why can't you just say miles per hour? Just because you use 'kilometer' in a sentence doesn't make you more authoritative. Because you don't want to be understood, as they say on Shark Tank, "For that reason, I'm out."

  50. Ryan Smith says:

    What about gravity

  51. Europa H2O Alien says:

    Thumbs down for the full length non-skippable ad.

  52. Pandu Bintang says:

    just wait until 2063 when zefram cochrane fly the phoenix…

  53. murphynapoleon says:

    Kilometers per hour means nothing to us. What are you, a scientist, a European, or just a smart ass? Can the metrics, this is America!

  54. Joshua Henderson says:

    Light speed is just a pipe dream never gonna happen before Humanity destroys itself.

    Just a side not guys this website can get you some easy money on the side if your bored. It has Easy Surveys to get gift cards from Amazon and some other places give it a try it works

  55. Σigma says:


  56. forever tipsy says:

    silly question maybe. but imagine you was in a plane that could travel as fast or at the speed of light. you used it to stay within the the earths atmosphere. you fly it around in circles around the planet.

    would the plane be in darkness? would light be able to reflect off it ?

  57. litltoosee says:

    What about the speed of thought?

  58. GlobalFortuneRecordingAcademy says:


  59. jdL powell says:

    you say "it's an impossible goal"….I say "goodbye dumbass"

  60. Brother Alaric says:

    Light Speed is Too slow . . we have to go to . .Ludicrous Speed .. .

  61. rationalguy says:

    We don't need to travel faster than light, even if it were possible. Time stops at that speed.

  62. Louie K says:


  63. aegisgfx says:

    lol we aint going anywhere, most of america worships an illiterate rapist..

  64. Fabian Tarantino says:

    If light has no mass, how can it exert a force on a solar sail?

  65. Frank Ocasio says:

    There is one thing that can travel faster than light,That is light can travel faster than itself.

  66. Don Jones says:

    wasn't light sail debunked? something about inverse square law and how minute energy you would get once u pass the solar system?

  67. Cody SwiftCaster says:

    We already perfected all that. The thing is not many people know about it. Unless you al paid attention to the ancient ancestors of the human race they taught all this and then later people grew ignorant and then was lied to and brain washed to be below average and lied that no one is perfect lol

  68. Video Storage says:

    Bajillion Gigawatz !

  69. Junn Kit Wong says:

    if we unable to speed up, slow light to snail will still allow us to FTL

  70. Mlaggione says:

    i guess you didnt hear about miguel alcubierre theoretical warp drive…

  71. h3lix86 says:

    how about we quit pissing away trillions on the military industrial pissing contest and trying to find better ways to kill eachother and instead focus on advancing all of mankind? oh, sorry i forgot. that doesnt make companies, and politicians rich. my bad

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